PURPOSE: A quality screening device of a semiconductor memory screens poor semiconductor memories within the time that can be assigned in a process for all word lines by using a boost voltage generating circuit. CONSTITUTION: A voltage comparator (COM) generates an activation signal by comparing an input voltage and a reference voltage. A voltage generator (GEN) generates a boosted boost voltage in response to the activation signal and feeds back the boost voltage to the input voltage. A counter (CNT) is connected to the voltage generator and counts the number of the activation signals. A determining unit determines a semiconductor memory as a fault when the counted number is over a target setting value. An output unit outputs the counted number.
